Nylon latent-crimp yarn having outstanding elasticity and cool feel

ABSTRACT

The present invention relates to a nylon latent-crimp yarn having outstanding elastic properties and cool feel, and is characterized in that a nylon 64 random copolymer (A) and one type of polymer (B) selected from nylon 6 and nylon 66 are subjected to conjugate spinning on a yarn cross-section in a side-by-side form. The nylon latent-crimp yarn according to the present invention has outstanding dyeing properties, dye fastness and elasticity, and exhibits high official moisture regain and a good cool feel. Also, the nylon latent-crimp yarn according to the present invention is inexpensive to produce, is highly suited to production, and also has outstanding yarn uniformity. For this reason, the nylon latent-crimp yarn according to the present invention is particularly useful as a fabric material for outdoor wear which is used like an elastic breathable waterproof polyurethane film.

TECHNICAL FIELD

The present invention relates to a nylon latent-crimp yarn having outstanding elasticity and cool feeling, and specifically to a nylon latent-crimp yarn having outstanding elasticity and cool feeling, in which (i) a nylon 64 random copolymer and (ii) a nylon 6 polymer or nylon 66 polymer are subjected to conjugate spinning on a yarn cross-section in a side-by-side form, thus to provide excellent dyeing properties, dyeing fastness and elasticity, and exhibit a high official moisture regain and a good cool feeling.

BACKGROUND ART

Nylon stretchable yarns have a production technique similar to that of polyester-based stretchable yarns. However, in purposes of use, the polyester-based stretchable yarns are widely used mostly for T-shirts, jackets, trousers or the like, and are recently used for composite yarns with other materials. However, since the nylon stretchable yarns are mainly used for outdoor wears, inner wears and socks, there is a difference in terms of use.

However, when the high stretchable polyester yarns are used as a material for a fabric which is used together with a stretchable moisture-permeable and waterproof polyurethane film, there are problems that dyeing properties are deteriorated, and dyeing properties, abrasion resistance and cool feeling are decreased.

As a result, there is a trend that use of the nylon stretchable yarns is greatly increased as the material for the outdoor wears in recent years.

As a first conventional technique for manufacturing the nylon stretchable yarns, a method of manufacturing nylon 66 stretchable yarns by drawing and false twisting nylon 66 at a high temperature during a false twisting process has been used.

The above-described conventional method is a method in which nylon 66 half-drawn yarns (POY) having a high melting point is false twisted by a low speed at a high temperature using a pin false twisting method or a disk false twisting method, to form crimps on non-aligned yarns by a physical method. The manufactured nylon 66 stretchable yarns have a high crimping rate and exhibits elasticity on the fabric.

However, the case of the above-described first conventional method has problems as follows. The nylon 66 is not produced for closing in Korea, and is imported at relatively high prices compared to the nylon 6, due to the use of hexamethylene diamine which is an expensive raw material. Therefore, the manufacturing cost is increased, and due to false twisting by a low speed at a high temperature, productivity is decreased. Further, since a high crimping rate is required at a high temperature, there is a high probability of non-uniformity occurring on the yarns.

As a second conventional technique used to manufacture the nylon stretchable yarns, there is a method in which a nylon 66 polymer and a nylon 6 polymer, which have a 4 to 5% difference in a shrinkage rate in boiling water, are subjected to conjugate spinning on the yarn cross-section in a side-by-side form, to manufacture nylon latent-crimp yarns.

However, the second conventional method has problems that, since a difference in the shrinkage rate in boiling water between the nylon 66 polymer and the nylon 6 polymer is low about 4 to 5%, it is difficult to naturally exhibit the crimps, and an occurrence of the crimps on the fabric is more markedly decreased than the occurrence of the crimps in a yarn state.

As another conventional technique used to manufacture the nylon stretchable yarns, there is a method in which nylon polymers having different relative viscosities (RV) from each other are subjected to conjugate spinning on the yarn cross-section in a side-by-side form, to manufacture nylon latent-crimp yarns. However, since the nylon is spun at a high spinning speed of 3,000 m/min or higher, there are problems that a phenomenon in which yarns are curved below a spinning spinneret due to a difference in the relative viscosity occurs, or it is difficult to produce in a commercial scale by a great decrease in spinning property and yarn productivity due to a decreased spinning speed.

DISCLOSURE Technical Problem

It is an object of the present invention to provide a nylon latent-crimp yarn having outstanding elasticity and cool feeling which has excellent dyeing properties, dyeing fastness and elasticity, and high official moisture regain to exhibit a good cool feeling, and is capable of manufacturing at low manufacturing cost and high productivity.

Technical Solution

In order to accomplish the above object, there is provided a nylon latent-crimp yarn having outstanding elasticity and cool feeling, which is characterized in that a nylon 64 random copolymer (A) and one polymer (B) selected from nylon 6 and nylon 66 are subjected to conjugate spinning on a yarn cross-section in a side-by-side form.

The nylon 64 random copolymer (A) includes 10 to 30 mol % of pyrrolidone which is a nylon 4 monomer, and 70 to 90 mol % of caprolactam which is a nylon 6 monomer.

Advantageous Effects

The nylon latent-crimp yarn according to the present invention may exhibit a good cool feeling due to excellent dyeing properties, dyeing fastness and elasticity, and have a high official moisture regain.

In addition, the nylon latent-crimp yarn according to the present invention may have a low manufacturing cost, high productivity, and excellent yarn uniformity.

Therefore, the nylon latent-crimp yarn according to the present invention may be especially useful as a fabric material for outdoor wears used together with stretchable moisture-permeable waterproof polyurethane films.

DESCRIPTION OF DRAWINGS

FIGS. 1 and 2 are schematic views illustrating a cross-section of a nylon latent-crimp yarn according to the present invention.

FIG. 3 is an electron microscope photograph of the nylon latent-crimp yarn of the present invention before performing a weaving process.

FIG. 4 is an electron microscope photograph of the nylon latent-crimp yarn of the present invention after performing the weaving process.

BEST MODE

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

A nylon latent-crimp yarn according to the present invention is characterized in that, as illustrated in FIGS. 1 and 2, a nylon 64 random copolymer (A) and one polymer (B) selected from nylon 6 and nylon 66 are subjected to conjugate spinning on a yarn cross-section in a side-by-side form.

FIGS. 1 and 2 are schematic views illustrating a cross-section of the nylon latent-crimp yarn according to the present invention.

The nylon 64 random copolymer (A) includes 10 to 30 mol % of pyrrolidone which is a nylon 4 monomer, and 70 to 90 mol % of caprolactam which is a nylon 6 monomer, and has a molecular weight of 70,000 to 120,000 g/mol and a polydispersity index of 1 to 2.

The nylon 64 random copolymer (A) is manufactured by performing anion-addition polymerization of caprolactam and 2-pyrrolidone, such that it has a low crystallinity of about 50% or less, a low melting point, and a high moisture regain, and thereby it is difficult to be used as engineering plastic. However, since it has proper strength and elongation, it is suitable to be used for clothing.

On the other hand, the nylon 46 polymer is manufactured by polycondensation of 1,4-diaminobutane and adipic acid, such that it has the highest crystallinity among the nylons pressurized at room-temperature, a high melting point, an excellent frictional resistance, a low deformation modulus, and an excellent resistance against oil and grease, and thereby it is mainly used as engineering plastic.

It is preferable that the weight ratio of the nylon random copolymer (A) to the one polymer (B) selected from nylon 6 and nylon 66, which are subjected to conjugate spinning on the yarn cross-section in a side-by-side form, is 25 to 50:75 to 50.

The nylon latent-crimp yarn according to the present invention has a shrinkage rate in boiling water of 30 to 50%, a crimping rate of 20 to 50%, and an official moisture regain of 5 to 8%.

The nylon 64 random polymer (A) has a relative viscosity (RV) of 2.4 to 3.0 measured by a sulfuric acid viscosimetric method, a melting point of 150 to 190° C., and a specific gravity of 1.11 to 1.13 g/cm³.

The one polymer (B) selected form nylon 6 and nylon 66 has a relative viscosity (RV) of 2.4 to 2.7 measured by the sulfuric acid viscosimetric method.

The nylon 64 random copolymer (A) is obtained by performing anion or bulk polymerization in a ratio of 70 to 90 mol %:10 to 30 mol % in contents of caprolactam which is a nylon 6 polymer monomer to pyrrolidine which is a nylon 4 polymer monomer.

In this regard, there are disadvantages that, as the mole ratio of caprolactam is increased, the properties of nylon 6 becomes strong, the melting point is increased, and the official moisture regain is decreased, such that it becomes equivalent to common nylon 6 and nylon 66 in terms of the above-described properties. Pyrrolidone may be obtained by decomposition of enzyme from cellulose, and thus it is widely known as a biochemical-based material. Nylon 4 is a polymer of butyrolactam (also referred to as 2-pyrrolidone or α-pyrrolidone), and is known to form a polymer as 2-pyrrolidone ring is opened under a specific condition. A high-contraction polymer prepared as described above has a shrinkage rate in boiling water of 30% to 60% when spinning by common yarns, and has a melting point of 150 to 190° C. and a relative viscosity (RV) in a range of 2.4 to 3.0 measured by using the sulfuric acid viscosimetric method. Since such a relative viscosity is similar to that of nylon 6 or nylon 66, it is possible to improve spinnability during manufacturing the latent-crimp yarn, and manufacture the yarns without big remodeling even if using existing conjugate spinning facilities.

Pyrrolidone which is a nylon 4 monomer is a biochemical-based raw material, and it may be used as an environmentally friendly material. In an age of current high oil prices due to depletion of fossil fuels, the number of consumers interested in the environmentally friendly material is rapidly increasing. Further, as a material having an image of not destroying the natural environment by using it for clothing, it is suitable as textile to be used in the future for which resource deletion is expected.

However, pure nylon 4 has a disadvantage that, ranges of processing temperature and decomposition temperature for processing during molten spinning are very similar to each other due to a high melting point, such that it is not possible to be processed. Further, since the pure nylon 4 has a high moisture regain, it is not suitable as engineering plastic.

When using the nylon 4 for clothing, since it contains a lot of amide group compared to common nylon, it shows strong hydrophilic properties. Therefore, in the present invention, by using the nylon 64 random copolymer obtained by copolymerizing the nylon 4 and nylon 6 in a constant ratio, it is possible to secure the processing temperature due to decreasing the melting point and control the crystallinity, and thereby exhibiting high-contraction performance. When side-by-side conjugate spinning is used by using a high-contraction polymer which is a copolymer of nylon 4 and nylon 6, moisture content is increased by a high-contraction polymer exposed on the surface. Therefore, touch feeling is improved when clothing contacts the human skin, and pleasantness may be provided to a wearer due to a high moisture content. Further, by absorbing and maintaining the moisture of the human skin, it is possible to provide not only feel comfortableness at all times but also cool feeling to the wearer in summertime due to a higher moisture content than that of the common nylon. In general, it can be said in the same vein that the cellulose-based textile may exhibit more excellent cool feeling.

Further, the nylon 64 random copolymer is stable in terms of spinnability and has a low spinning temperature. When performing conjugate spinning the nylon 64 random copolymer together with the nylon 6 rather than nylon 66, it is possible to spin even at a low temperature, and thereby providing an energy saving effect.

In the case of nylon 64 and nylon 610, in which the nylon 6 and nylon 4 is copolymerized in the same molarity, such a high-contraction characteristic is not exhibited, but the moisture content thereof is decreased. However, in the case of the nylon 64 random copolymer, the formation of molecular chains in polymer is randomly changed, so as to exhibit high contractibility. Thereby, during side-by-side conjugate spinning, contraction makes progress greatly toward the nylon 4 copolymer, so that it is possible to show an effect like latent crimp. If there is a difference in the shrinkage rate due to processing, a spring-shaped structure is formed by the yarns having a spiral structure, and it is possible to manufacture a stretchable fabric through contraction processing during the processing after weaving the fabric. Further, since two nylon-based polymers are used, dyeing is possible with acid dye, and since a large quantity of amine group, which is a dyeing site, is contained, it is possible to manufacture the latent-crimp yarns with excellent dyeing properties and excellent dyeing fastness.

Hereinafter, the present invention will be described to more concretely with reference to examples and comparative examples. However, it will be apparent to those skilled in the related art that the scope of the present invention to be protected is not limited only to the following examples.

EXAMPLE 1

30 mol % of pyrrolidone and 70 mol % of caprolactam were obtained by performing anion polymerization, and a nylon 64 random copolymer having a melting point of 170° C. and a relative viscosity (RV) of 2.6 were discharged at a spinning temperature of 260° C. by a side-by-side conjugate spinning method using an extruder, respectively. After spinning was performed so as to be conjugated at a weight ratio of 50:50 in a spinning pack, cooling and coagulating were performed by using a cooling chamber. Winding was performed through a first godet roller and a second roller at a speed of 3000 m/min, to prepare 85-denier/24 filament half-drawn yarns.

The half-drawn yarns wound as described above were drawn at a spinning speed of 500 m/min and a drawing ratio of 1.26 by using a drawing winding machine to wind the drawn yarns of 70-denier/24 filament spec to manufacture nylon latent-crimp yarns.

Comparative Example 1

Nylon 66 was spun at a spinning speed of 3000 m/min by using a common nylon first heater half-drawn yarn manufacturing facility, to prepare 85-denier/24 filament half-drawn yarns. By setting the temperature of the first heater to 220° C. or higher and passing through a pin type false twisting device at a drawing ratio of 1.3 and a spinning speed of 300 m/min, 70-denier/24 filament highly stretchable false-twisted yarns were manufactured.

Comparative Example 2

Nylon 6 and nylon 66 were discharged out by using an extruder, respectively, and spun so as to be conjugated in the spinning pack in an area ratio of 50:50.

Subsequently, cooling and coagulating were performed by using a cooling chamber and winding was performed through a first godet roller and a second godet roller at a speed of 3000 m/min, to manufacture half-drawn yarns.

The half-drawn yarns wound as described above were drawn and wound at a spinning speed of 700 m/min and in a drawing ratio of 1.23 using an elongation winding machine to manufacture highly stretchable yarns.

TABLE 1 Property measured results Shrinkage rate in Official boiling Crimping moisture Qmax Section water (%) rate (%) regain (%) (W/cm²) Example 1 42 35 7.5 0.25 Comparative 32 26 4.5 0.18 Example 1 Comparative 12 3 4.5 0.17 Example 2

Properties of Table 1 were evaluated by the following method, respectively.

Shrinkage Rate in Boiling Water Measuring Method (Company Method)

1) After winding 20 times on a hank the specimens to be measured, insert clips to prepare specimens. Make 3 specimens per a sample.

2) Tie both ends of the specimens to be a length of 50 cm, and apply an initial load thereto to measure the length.

-   -   The initial load is set to have a test yarn thickness (denier)         of 1/10 g.     -   For example, when the test yarn have a thickness of 50 denier,         hang a 5 g weight.     -   Measuring length: L0

3) Leave the specimens for 24 hours under a constant temperature and humidity atmosphere.

-   -   About 25° C., 65%     -   Maintain initial load as it is

4) Measure test yarn after leaving the specimens

-   -   Measured length: L1     -   Maintain initial load as it is

5) Delay calculation formula

-   -   Delay

$\left( L_{2} \right) = {\frac{L_{0} - L_{1}}{L_{0}} \times 100(\%)}$

6) Immerse a delay test yarn (L2) in boiling water (90 to 95° C.) for 30 minutes

-   -   Immerse the whole of test yarns in boiling water     -   Maintain initial load as it is     -   (Take caution for the weight not to touch a bottom in the         initial load)

7) Take out the test yarns, wipe moisture and leave it for 24 hours at a constant temperature and humidity atmosphere

-   -   About 25° C., 65%     -   Maintain initial load as it is

8) After leaving the test yarns, measure the length thereof

-   -   Measured length: L3     -   Maintain initial load as it is

9) Boiling water calculation formula

-   -   Shrinkage rate in boiling water

$\left( {L\; 4} \right) = {\frac{L_{2} - L_{3}}{L_{2}} \times 100(\%)}$

Crimp Rate Measuring Method 1. Specimen preparation—After winding 10 times on the hank the specimens to be measured. Insert clips on both sides to prepare specimen. Make 3 specimens per a sample.

2. When temperature of a steam bath reaches a predetermined temperature, insert clip into a ring and put the specimens into a glass guide that is made so as to be put into the steam bath, and pick it up carefully to put it into the steam bath.

3. After performing boiling water treatment for 20 minutes, take the specimens out and remove moisture and leave it for 12 hours.

4. Calculate the initial load—mark den/25 g and static load—mark den*2 g, and the crimping rate is measured by the following formula.

5. Apply the static load+initial load to the specimens, and the length is measured after 2 minutes−L

6. Remove the static load and the length is measured after 3 minutes with the initial load only−L1

7. Calculation formula

${{Crimping}\mspace{14mu} {rate}} = {\frac{L - L_{1}}{L} \times 100}$

Cool Feeling Measuring Method

1. Testing environment: 20° C., 65% RH

2. Testing equipment: KES-F7 Thermo Labo II (Kalto Tech)

3. Qmax value: The value of measuring the instantaneous wattage required for correcting temperature when the fabric contacts a unit sensor

4. Test preparation: Use a circular knitting machine to knit a test fabric, and refining and dyeing were executed in the same method, modifying width was performed to prepare a test piece.

DESCRIPTION OF REFERENCE NUMERALS

-   A: nylon 64 random copolymer -   B: nylon 6 or nylon 66 polymer

INDUSTRIAL APPLICABILITY

The nylon latent-crimp yarn of the present invention is useful as yarns for clothing, especially for a fabric material for outdoor wears. 

1. A nylon latent-crimp yarn having outstanding elasticity and cool feeling, the nylon latent-crimp yarn is characterized in that a nylon 64 random copolymer (A) and one polymer (B) selected from nylon 6 and nylon 66 are subjected to conjugate spinning on a yarn cross-section in a side-by-side form.
 2. The nylon latent-crimp yarn according to claim 1, wherein the nylon 64 random copolymer (A) includes 10 to 30 mol % of pyrrolidone which is a nylon 4 monomer, and 70 to 90 mol % of caprolactam which is a nylon 6 monomer, and has a molecular weight of 70,000 to 120,000 g/mol and a polydispersity index of 1 to
 2. 3. The nylon latent-crimp yarn according to claim 1, wherein the weight ratio of the nylon 64 random copolymer (A) to the one polymer (B) selected from nylon 6 and nylon 66, which are subjected to conjugate spinning on the yarn cross-section in a side-by-side form, is 25 to 50:75 to
 50. 4. The nylon latent-crimp yarn according to claim 1, wherein the nylon latent-crimp yarn has a shrinkage rate in boiling water of 30 to 50%, a crimping rate of 20 to 50%, and an official moisture regain of 5 to 8%.
 5. The nylon latent-crimp yarn according to claim 1, wherein the nylon 64 random polymer (A) has a relative viscosity (RV) of 2.4 to 3.0 measured by a sulfuric acid viscosimetric method, a melting point of 150 to 190° C., and a specific gravity of 1.11 to 1.13 g/cm³.
 6. The nylon latent-crimp yarn according to claim 1, wherein the one polymer (B) selected form nylon 6 and nylon 66 has a relative viscosity (RV) of 2.4 to 2.7 measured by the sulfuric acid viscosimetric method. 